Implication of abandoned post‐quarry sites on avifauna composition for strategic landscape restoration in Ndarugu, Kiambu, Kenya

Abstract

Abandoned post‐quarry sites have potentiality to be remodeled into natural‐wilderness areas, a desire especially in rapidly urbanizing and transforming landscapes. However, paucity of ecological information on post‐quarry sites limits nature‐based restoration, especially in the sub‐Saharan tropical landscape. This study investigated avifauna composition of post‐quarry sites in Ndarugu, Kenya, relative to non‐quarried sites for conservation role prioritization. Birds were censused in 166 point count stations using the fixed‐radius distance method. Land use land cover types within each point provided the variables for explaining bird occurrence. Observed bird species were classified into functional guilds, avifaunal composition assessed, and bird data subjected to multivariate analysis. In total 158 species, 128 in post‐quarry and 123 in non‐quarried sites, were recorded. Bush‐ and forest‐related species were dominant, constituting over 55% of total observed birds, in both site categories. Six wetland‐related species were detected only in quarried sampling sites. Mann–Whitney statistical tests returned a significant effect of land use category on bird species richness, abundance, and diversity, all higher in post‐quarried than in non‐quarried sites (p < 0.05). Emergent natural shrubs, quarry cliffs, and cultivated farms were most influential to bird community structuring. Nonmetric multidimensional scaling and cluster analysis revealed four functional groups of birds whose species richness increased with number of post‐quarried sampling sites in a cluster. Unique physical features of post‐quarry sites and emergent vegetation types, can be partially mimicked in nature‐oriented rehabilitation planning for long‐term social and ecological benefits.